The results of this study can serve as a benchmark for monitoring progress toward narrowing the gap in survival. Cancer Epidemiol Biomarkers Prev; 26(1); 145-51. ©2016 AACR.

We aimed to compare cancer survival in Ontario First Nations people to that in other Ontarians for five major cancer types: colorectal, lung, cervix, breast and prostate. A list of registered or “Status” Indians in Ontario was used to create a cohort of over 140,000 Ontario First Nations people. Cancers diagnosed in cohort members between 1968 and 2001 were identified from the Ontario Cancer Registry, with follow‐up for death until December 31st, 2007. Flexible parametric modeling of the hazard function was used to compare the survival experience of the cohort to that of other Ontarians. We considered changes in survival from the first half of the time period (1968–1991) to the second half (1992–2001). For other Ontarians, survival had improved over time for every cancer site. For the First Nations cohort, survival improved only for breast and prostate cancers; it either declined or remained unchanged for the other cancers. For cancers diagnosed in 1992 or later, all‐cause and cause‐specific survival was significantly poorer for First Nations people diagnosed with breast, prostate, cervical, colorectal (male and female) and male lung cancers as compared to their non‐First Nations peers. For female lung cancer, First Nations women appeared to have poorer survival; however, the result was not statistically significant. Ontario's First Nations population experiences poorer cancer survival when compared to other Ontarians and strategies to reduce these inequalities must be developed and implemented.

Background: Indigenous populations in Canada and abroad have poorer survival after a breast cancer diagnosis compared with their geographic counterparts; however, the influence of many demographic, personal, tumor, and treatment factors has not been examined to describe this disparity according to stage at diagnosis.Methods: A case-case design was employed to compare First Nations (FN) women (n ¼ 287) to a frequencymatched random sample of non-FN women (n ¼ 671) diagnosed with breast cancer within the Ontario Cancer Registry. Women were matched on period of diagnosis (1995-1999 and 2000-2004), age at diagnosis (<50 vs. !50), and Regional Cancer Centre (RCC). Stage and other factors were collected from medical charts at the RCCs. Survival was compared using an adjusted Cox proportional hazards model and stratified by stage at diagnosis (I, II, and III-IV). Determinants of survival in FN women stratified by stage at diagnosis were also modeled.Results: Survival was more than three times poorer for FN women diagnosed at stage I than for non-FN women (HR ¼ 3.10, 95% CI ¼ 1.39-6.88). The risk of death after a stage I breast cancer diagnosis was about five times higher among FN women with a comorbidity other than diabetes (HR ¼ 4.65, 95% CI ¼ 1.39-15.53) and was more than five times greater for women with diabetes (HR ¼ 5.49, 95% CI ¼ 1.69-17.90) than for those without a comorbidity.Conclusions: Having a preexisting comorbidity was the most important factor in explaining the observed survival disparity among FN women.Impact: Improving the general health status of FN women could increase their survival after an early-stage breast cancer diagnosis. Cancer Epidemiol Biomarkers Prev; 20(10); 2160-7. Ó2011 AACR.